Automatic telephone-exchange.



c.L.Go0DRuM. AUTOMATIC TELEPHONE EXCHANGE..

APPLICATION lFILED IIIY I. 1909.

Patented Nov. 28, 1915.

7 SHEETS-SHEET I.

DDIIIIINM MDS kbu S @Sw 9o IIIIIIWDD EEIIIIIIIN .Q ab@ S n.0 IIIIIWEU @www avvento C. Ll GOODRUM.

AUTOMATIC TELEPHONE EXCHANGE.

APPLICATIQN EILD MAY l. 1909.

7 SHEETS-SHEET 2.

31am/nien Witnesses C. L. GOODRUIVI.

AUTOMATIC TELEPHONE EXCHANGE. APPLlcATloN FILED MAYI. 1909.

Patented Nov. 23, 1915.

i SHEETS-SHEET a.

C. L. GQODRUM.

AUTOMATIC TELEPHONE EXCHANGE.

APPLICATION man MAY l. 1909.

I SHEETS-SHEET 4- Patented Nov. 273, 1915.

c; L. Gooouwl.n AUTOMATIC TELEPHONE EXCHANGE.

APPLICATION HLED MAY l |909.

' Patented Nov. 1 SHEETS-SHEET s.

SSN QLTIQGHQ .h S

@Hom-'nuff C. L. GOODRUM.

AUTOMATIC TELEPHONE EXCHANGE. APPLICATION man MMI. 1909.

Patented Nov. 23, 1915.

7 SHEETS-SHEET 6- C. L. GUODRUNI.

AUTOMATIC TELEPHONE EXCHANGE. APPucATloN FILED mm1, 19'09.`

Patented Nov. 213, i915.

7 SHEETS-SHEET 7.

CHARLES L. GOODRUM, `F URBANA, OHIO, ASSIGNOR, BY MESNE ASSIGNMENTS, TO WESTERN ELECTRIC COMPANY, 0F NEW YORK,4 IN'. Y., A CORPORATION OF ILLINOIS.

AUTOMATIC TELEPHONE-CNGE.

Specification of Letters Patent; l

Patented-Nov.. 253, IAI.

Applicationled May 1, 1909. Serial No. 493,396.

To all whom t may concern:

Be it known that I, CHARLES L. GooDRUM, a vcitizen of the United States, residing at Urbana, in the county of Champaign and State of Ohio, have invented certain new and useful Improvements in Automatic Telephone-Exchanges, of'which the follow'-A ing is a specification.

My invention relates to improvements in automatic telephone exchanges and the object of my invention is to provide means by which incoming calls are distributed over a series of switches less than the total number of lines and without the aid of distribution switches, the constructions and arrangements beingsuch that the switches shall be common to all the groups, so that if a switch relating to one group is busy the call would be passed on to the switch in another group. i

A further object of the invention is to so arrange the subscribers circuits that the incoming calls shall be handled by the finder switch to which the group is normally assigned by the least possible movement arrangement of the subscribers circuits to the different inder switches, the arrangement being shown adapted to flat switches. Fig. 3 shows a similararrangement of circuits and connections as applied to the twomovement, or what is known as the up-andaround switch. Fig. 4 is a diagrammatic 'view showing the connections and circuits from the subscribers stations to the finder switch and showing the arrangement of the connections from one switch to another so that the incoming falls are distributed in the various switches, two switches only being indicated. Fig. 5 is a diagrammatic view showing the arrangement of the distributing or starting circuit. Fig. 6 is a diagrammatic view showing the operative circuit for continuing the operation of the switch after the same has been started over the starting circuit. Fig. 7 is a diagrammatic View showing a modification,

Like parts are represented by similar characters of reference in the several views. A general outline or general plan of my lmprov'ed automatic telephone system is as follows: I employ the usual l'ine and cutoff relaysv for each line, and I employ av certain number of finder switches less than the total number of'l subscribers lines to which these subscribers lines are connected in multiple. 'Ihe proportionate number of finder switches to the subscribers lines may be varied at will and will be dependent upon the average number of calls originating in any particular group of subscribers.

In my illustrations I have used ten per cent. as the basis fordistribution or, in other words, for each fifty subscribers I use tive finder switchesand a corresponding number of selector switches and connector switches, it having been found, by experience, that in an ordinaryv exchange, say, from one to five thousand subscribers, ten inder switches for each one hundred subscribers are sufficient to handle the incoming calls. It will be seen later, however, that this number may be varied to suit any condition without in any way changing or modifying the system.

The subscribers lines are arranged in groups, each group preferably consisting of as many subscribers lines as the total number of subscribers lines divided by the number of switches assigned to said subscribers lines. In other words, if the percentageof switches employed is ten per cent. of the lines, then each group would preferably consist of ten lines. If the switches to be employed were to be 12J; per cent., then the group would preferably consist of eight lines. If the number of switches were to be increased to 20 per cent., the groups could be decreased to lfive lines. In the illustra tion I have shown ten lines in each group. Each group of lines is connected in multiple vto the various switches assigned to that group. rIhat is to say, on the basis of ten per cent., each group of ten lines out of the fifty lines would be preferably assigned toI ive switches. I also employ for each group of lines a starter wire which is primarily connected to one of the switches, to which the lines of any group are connected and I arrange this starter wire so as to be eXtended to other switches of the group and to the switching relay thereof, so that when a call `is originated in any group and a finder position.

switch is operated to find that line, the starter wire will be cut out of c1rcu1t with that' switch, but extended successively to such of the other switches as are in normal In order toi-obtain the best results and provide for finding' the line of a calllng -subscriber with -the least eHort and movei the switches assigned to the total number' of groups, incoming calls in either of said groups will normally -be assigned to one particular switch of the group of finder switches, but in the event that that particular finder switch is in use, then the call will be passed on to any other finder switch of lthe group which is not in use. In making this' connection I preferably arrange the subscribers circuits so that the first group,

say, of ten lines, is assigned to the first ten contacts of the first switch, the second group (of ten lines) is assigned to thel first ten points or contacts of the second switch, a third group is assigned to the first set of contacts of the third switch and so on. The multiple connections of these different groups are then connected to the different switches to succeeding series of contacts in different switches. That is to say, the ten lines coming into the first ten contacts of the first switch are connected to the second ten in the second switch, the third ten in the third switch, the fourth ten in the fourth switch and the fifth ten in the flfth switch. The second group of ten is connected to the first ten in the second switch, the second ten in the third switch, the third ten in the fourth switch, the fourth ten. in the fifth switch and to the second ten in the first switch. l

As shown in diagram in Fig. 2, the group of lineslcoming into the first ten of the third switch would be connected to the second ten of the fourth switch, the third ten of the fifth switch, the third ten of the first switch and the fourth ten of the second switch and the fifth ten of the third switch. It is obvious that if more than fifty lines are used, the multiple connections for the second,

' third, fourth and fifth switches of the group,

continue to operate by electric energy received from a local circuit, of which a terminal on the switching device is a part, l(see Fig. 6) so that the switch operating mechanism receives an impulse from each contact in the bank so long as the line relay of that.particularsubscriber is in its normal position, but which receives no current when the line relay has been operated by closing the subscribers line. For the purpose of vthis invention it is only necessary to show the method. of starting the switching mechanism, as the starting of any switching de- \yice by the closing of any subscribers line renders it inoperative for any other subscribers line.

I will now proceed to describe the arrangements of the circuits and the operation of making a call from any group of subscribers lines.

Fig. 1` will show the eneral arrangement of the line and cut-o relay, the nder switches, the first and second lselector switches and the connector switches. As before stated, the finder switches are arranged in groups of five, the selector and connector switches are also preferably arranged in groups of fives. The line and cutoff relays are arranged in banks of fifty, that is, fifty relays correspond to five switches. The subscribers lines, as above stated, are, however, arranged in groups of tens, and the line and cut-off relays are also arranged in groups of tens, five groups in each bank.

Referring to Fig. 5, the line relays of any group of ten subscribers are adapted to close a circuit on the starting wire common lto that group and in Fig. 5 I have shown the relays marked 1, 11, 21, 31 and 41 as representing the first line relay of each group, it being understood that there will be ten such relays in each group.

The finder switches relating to the fifty lines, represented by five groups of ten lines each, are marked al, a2, a3, a? and. a". Each of these switches, except the last one` a5, has been operated by the closing of the line relay of the group, so that the starter Wire has been cut through or extended from each of the groups to switch, la5. This is accomplished as follows: Each of the switches, al, a2, a3, a4 and (this provided with an auxiliary switch or circuit closer, b, which, when the switch is in normal position, is adapted to engage a contact, b1, and, when the switch is operated or is off-normal, to engage a contact, b2. There are three relays, c d and e, associated with each switch, thel relay, c, being the motor magnet which drives the switch from the impulses received from the line, d and e being one a quick and the other a slow relay, which are used in operating the switch and making the connections, as will be explained more fully hereinafter.

,incinte Upon the closing of any line in any group,

say, from a subscribers station A, a circuit will be closed through the line relay in the usuall manner and as follows: From switch hook A1, contact 2, wire. 3, one winding of relay 1 (one) battery, other winding of relay 1, wire 4 back to hook A1. Illhis operates the relay 1 (one) and closes thecircuit from ground at 5, through contact 6, circuit closer 7, line 8, circuit closer b, contact b1, line 9, contact 10, circuit closer 12, line 13, switch relay d, wire'14, battery 15, to ground at 16. rlhis operates the switch relay, d, and closes the circuit from ground 17, contact 18, circuit closer 19, wire 20, motor magnet, c, wire 21, battery 15, to ground at 16, thus operating the motor magnet c. At the same time a circuit is closed from ground 17 (16 in Fig. 6), contact 18, circuit closer 19, wire 22, through relay e, wire 23, battery 15, and ground at 16. The closlng of the circuit through the motor magnet, c, causes the switch, al', to advance one step or to off-normal position, which closes the switch or circuit closer, b, against the contact, b2, and open the circuit at b1. 'lihe relay, e, being a slow relay will not immediately be released and the motor magnet and relay, d, obtaining current through the line contacts or banks of the switch, al, will ad- Vance it until it finds the line operated, in the usual manner, after which the magnets, ai', c and e, will be restored and the starter wire, 8, will be extended through circuit closer, b, contact b2, line 24, contact 25, circuit closer 26, line 27, to switch or circuit closer lever b, on the finder switch a2, so that the subsequent operation of any line relay in that first group would close a circuit through the line 27 to the switch lever Z, contact b2, .wire 9, contact 10, circuit closing lever 12, wire 13, to relay d of the second switch a2, which, ythrough the circuits before described, would cause this switch to move one step or to oH-normal position, thus allowing the lever, b, to en.

gage with contact b2, and extend the starter line through line 24 and the relay contacts of the relay, e, relating to switch a2, to the switch lever, b, of the` third switch, and so on through the series.

As shown in Fig. 5, all the switches, except a5, have been started, hence a call originating in any line ofl any group will be transferred to switch a5. 1f it should come in on switch a5, 4the closing of the line relay 41 would close the circuit from ground 5, as heretofore described, through circuit closing lever, b, contact b1, line 10, and circuit, heretofore described, to relay, d5, relay e5, and motor magnet c5, as heretofore described. `Whenever any switch is released the off-normal switch, b, is closed to the contact b1, for that switch, so that if a second call should, originate in any group, say,

`in the line group containing relay 41, the

whicht if in normal position, will be operated, if not, 4thefcallwill be cut through,

'as before described,'to'the various other switches. y

It will be understood that, associated with each line, is a line relay a and lcut-od relay f, (see Fig. 4) which latter, so soon as the line 1s found by the finder' switch, is op.

eratedto cut off the line relay and restore it to normal position in the usual-way by wiper 33 engaging the contact 34 (corresponding to the line operated) thus placing ground on said contact and operating the cut off relay over the circuit from grounded wiper 33, contact 34, wires 35, 36, relay f, battery and ground as shownin Fig. 4, the wiper 33 being grounded in the usual way. lit will be understood that the starter wire 8 extends to a circuit closer 7, on each of the line relays, a., in a group. Fig. 4 also illustrates the method of connecting the different lines inA multiple to -the different switches. For instance, the lines from the station, A5, are connected in multiple to switches, a1 and a2. lin Fig. 4 the lines from this station are represented as termi- -nals No. 5 on the switch, a1, and connected nal 17 in the second group of ten in the,`

second switch, a2.

lin Figs. 2 and 3 li have shown how these multiple connections are made, Fig. 2 representing a flat switch. The lines` of the first group of ten are brought into the first contacts, Aas indicated at g1, in switch a1.' These same lines are connected in multiple to the second group of ten contacts in the second switch, as shown at g? in switch a2, to the third group of ten in the third switch, as shown at g3 on switch a3, the fourth group of ten in the fourth switch, as shown at g* on switch a4, and the fifth switch in the fifth group, as shown at g5 on switch a4". The next group of ten lines will be brought to the first ten contacts of switch a?, as shown at g1. These lines would `appear on the second group of ten on the on switch a?. The succeeding groups of lines would come into the first group Aof contacts on the succeeding switches and multiple to the other switches in the same way.

In the two-movement, or up-and-around, switch the connections would be arranged in the same'way, except that, instead of being arranged in groups around the bank, the groups would be placed in different levels, preferably five levels in each switch and ten contacts in each level. In this case, the rst group of ten would come into the -contacts on the first level of switch al, the second level of switch a2, the third level in switch as, the fourth level in switch a* and the fifth level in switch a". The second group would come into the'first level of switch a2, the second level of switch a3, the third level of switch c, the fourth level of switch a5 and the first level of switch as 'The next group would come to the first level of switch, a", second level of switch a4, third level of' switch a, fourth level of switch a1 and fifth level of switch a2, and so on throughout the series.

It will be seen thus that the ope-ration of any line relay'starts a switch to which that line relay is normally assigned. The starting of this switch will .extend the starter wire tojthe next switch, so that any line relay operated in the first group will have its call transferred to the second switch, but it will take the second group in this switch or,y in case of the up-and-around switch, it will take the second level and so on.

Any call arising in a group, which. is normally assigned to a certain switch, will always come in on the first group of contacts in that particular' switch, hence, in the normal working of the system, the first ten contacts of each switch are the ones that are used, but, in the event that the switch is busy, such call would be transferred to the next switch, which switch would find its line in the second group. If this switch were also busy it would be extended to the next switch and find its line in the third group and so on, so that, in the normal position, the switches are required to operate the least possible distance in finding the line and it is only in cases that the switches assigned to the lines are busy that the switches will be required to move over more than ten points to make the contacts.

In the above description I have described the number of switches as corresponding with the number of groups and, while this is lthe preferable arrangement, it is not necessary as it is obvious that one might have a larger number of groups with a smaller number of switches. For instance, ten groups of ten lines each might be accommodated on five switches, in which case, two

groups would be normally assigned to-each switch with 14the means described for extending the calls into the next switch in case that the part1cu1ar s/wltch 1s busy. So also it is not necessary to make the multiple conf nectionsl `from the last switch to any particular group back to the first, as these multiple connections may be extended from one group roriginating in the groups and, if it were a system where only a few calls are likely to arise at the same time, the number of switches can be reduced, while the groups of subscribers could remain the same. This is particularly true on the two-movement or up-and-a-round switch where the preferable and desirable number of subscribers in a group would be the number of contacts in a given level of which the desirable number is found to be ten, so it might be found that, where there were fifty lines and the probability of not more thany two calls originating at the same time, two switches might be arranged to handle the connections, although the numberof lines might be divided into. five groups, representing ve levels on the switch, so that, while the groups of lines are here described as being the same as the number of switches in a group, it does not necssarily follow that this should be always use Y It is also obvious that the number of switches might be considerably larger than the number of groups of subscribers in cases where a large number of calls might originate simultaneously in a single group. For instance, ten switches might be assigned to five groups. In this case, instead of making the groups smaller, the groups might remain the same and each group assigned normally to two switches and the multiple connections made to the switches in pairs instead of in units as shown in Fig. 7. The advantage of the system being its flexibility and its adaptability to anyV requirement in the relation of calls to the number of lines used.

Having thus described my invention, I claim:

1. In an automatic telephone system, subscribers circuits arranged in groups, finder switches each having a series of contacts ar- A ranged in groups and equal in number to the subscribers circuits in several groups, each group of subscribers circuits being connected to the first group of contacts in one of said switches and in multiple to succeeding groups of contacts .in different switches.

2. In an automatic telephone system, subscribers circuits arranged in grou s, a series of switches corresponding in num er to the number of groups, each of said groups being connected to the first group of contacts in oneOf said switches and connected n muldit tiple to succeeding groups of contacts in dierent switches, a starter wire common to all the subscribers circuits in one group and leading to a switch assigned to that group, and means for extending said starter wire to other or diierent switches when a switch to which it is normally extended has been operated.

l 3. ln an automatic telephone system, subscribers circuits arranged in groups, finder switches, each having a series of contacts arranged in groups, each group. of contacts corresponding in number to the subscribers circuits in a group, and each group of subscribers circuits being connected to the rst group of contacts in oneof said switches and in multiple to succeeding groups of contacts' in diiierent switches, as specified.

4. In an automatic telephone system, subscribers circuits arranged in groups, a series of switches each having contacts arranged in groups, each group corresponding in number to the number of subscribers circuits in a group, each of said roups of circuits being connected to the rst group of contacts in one of said switches and in multiple to succeeding groups of contacts in diderent switches, a starter wire common to all the subscribers circuits in one group leading to a switch assigned to that group, and means for extending said starter wire to other or different switches when a switch to which it is normally extended has been operated.

5. lin an automatic telephone system, l1ne circuits arranged in groups, a plurality of nder switches, multiple connections from each group to said inder switches, a starter wire common to the group of line circults, a switch relay connected to said starter wire which controls the movements of said switch to which said starter wire is connected, a line relay in each line circuit, said line relay being adapted to close the circuit over said starter wire and give said switch an initial movement over said circuit, an auxiliary switch actuated upon the operation of said nder switch to disconnect .said switch relay and extend the starting wire by a normally closed circuit to the next succeeding switch and a slow relay to hold open said normally closed circuit until the switch iirst started has concluded its operation.

6. ln an automatic telephone system, subscribers circuits arranged in groups, each group being connected in multiple to a plurality of iinder switches, a line relay in each subscribers circuit, and means connected with said relay for closing a circuit, a starting wire common to all the relays in one g'roup comprising a part of said circuit,

means for operating said finder switch, a

relay normally in circuit with said starter wire to co'ntrol said means, and an auxlli'ary switch connected w1th said finder swltch adapted when the viinder switch is operatedA to `extend said starter wire through a normally closed circuit to another`inder switch to which said subscribers line is multiply connected, and 4means for holding open said extended connection until the first switch has completed its operation.

7. In an automatic telephone system, a

series of subscribers. lines, a series of' switches, said subscribers lines being arranged in groups and-connected to said switches in multiple, a starter wire for each group, terminating ina switch normally assigned to said group, means for extending said starter wire to the switches of other groups when the first switch is operated, and

a circuit breaker in said starter wire extension and means for opening said extended starter wire while the switch is operating.

8. The combination with a series of elec tric circuits arranged in groups, switches.

less in number than the lines to which said lines are connected in multiple, a starter wire for each group normally terminating f in one of said switches, means for extending the starter wire to another switch when the, first switch is operated and means in said.

starter wire extension for holding open said extenslon during .the operation of the irst switch.

9. The combination with a progressivelyv movable switching mechanism, a series of lines arranged in groups and connected in multiple to different switches, a line relay in each line and a starter wire common to the lines of one group havin-g branches to each line relay, an operating circuit for each group also having circuit branches to said relay, means for closing the starting branch and opening the operating branch when the relay is operated, and means for extending said starter wire to -another switch when the first switch is operated.

10. lln an automatic telephone system,

subscribers circuits arranged in groups,

ascending sequence of preference.

11. ln an automatic telephone system, subscribers circuits arranged in groups, finder switches, each having a series of passive contacts arranged in groups and equal in number to the subscribers circuits in the vseveral groups, movable contacts, means providing for a determined order of preference between the various groups of station'- ary contacts and each movable contact,

whereby the4 group of lines represented by the rst preferred group of contacts in each switch are given preference in an ascending numerical sequence. in the remaining switches.

12. In an automatic telephone system, subscribers circuits arranged in groups, finder switches each having Va series of stationary contacts arranged in groups and equal in' number to the subscribers circuits in thc several groups, movable contacts, means to establish a determined order of preference between the various grou-ps of stationary contacts and each movable contact, whereby the preferred group of contacts of a particular switch will be given preference in an -ascending numerical sequence in the remaining switches.

13. In yan automatic telephone system, subscribers circuits arranged in groups, a plurality of linder switches less in number than the number of subscribers circuits, 'stationarycontacts to which said circuits are multiplied and coperating movable contacts, a preferred group of contacts in each switch adapted to be engaged by a minimum movement of the movable contacts of said switch and by progressively greater movements of the other switches, and'means -respon'sive to a call on any line to start the idle switch which can engage the stationary contacts of that line in the least movement.

14. In an automatic telephone system, subscribers circuits arranged in groups, a plurality of finder switches less in number than the number of subscribers circuits, stationary contacts to which said circuits are multiplied and coperating movable contacts, a preferred group of contacts in each switch adapted to be engaged by a minimum movement of the movable contacts of said switch and by progressively greater move` ments of the other switches, and means rcsponsive to a call on any line to start a switch which can engag'e the staionary contacts of that line in the least movement provided that switch is idle, or if that switch is busy to start the switch which can engage the stationary contacts of that line in the next least movement, or if the second switch is busy to start the switch which can engage the stationary contacts of a line in the next least movement and so continue through the plurality of switches providing they are busy to the switch which requires the maximum movement t`o engage the stationary contacts of the line.

In testimony whereof, I have hereunto set my hand this 16th da of April, 1909.

CHARL S L. GOODRUM. Witnesses:

JAMES S. BRAILEY, Jr., CHAs. I. WELCH. 

